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NASA is counting on Starship, a 400-foot-tall, super-heavy-lift rocket and spaceship system, to put its first astronauts on the moon under a $4.2 billion contract. Though the U.S. space agency has its own rocket and spaceship, Starship is expected to ferry the crew from lunar orbit to the moon's surface for the last leg of the journey.

Why does NASA want a propellant depot in space?
NASA and commercial partners are interested in space fuel stations because they could allow spacecraft to travel longer and farther into the solar system. Future missions could use ice on the moon to make propellant by splitting water molecules into hydrogen and oxygen. If engineers can figure out how to store super-cold liquids in space, whether they are launched from Earth or produced somewhere else, it could make a long-term stay on the moon possible and even support distant missions to Mars.

NASA has invested $370 million in over a dozen U.S. companies to develop the technology needed to store and transfer rocket fuel in space. That funding includes $53 million for SpaceX to demonstrate a propellant transfer, from tanker to ship, in orbit.

The U.S. space agency has chosen to use private vendors for moon landers to buy down the technical risks and costs of the Artemis program, which seeks to use the moon as a springboard for eventual missions to Mars. SpaceX was the first selected, and Blue Origin, billionaire Jeff Bezos' rival space company, was awarded the contract for Artemis V, a crewed mission slated for no earlier than 2029.

A system with vertical solar panels inside a reflective parabola, like a Compound Parabolic Concentrator (CPC), can increase energy output by concentrating sunlight onto the panels from multiple angles. While a basic parabolic reflector must be precisely aimed at the sun, a CPC is designed to collect and concentrate light over a range of angles, and a secondary reflector can be added to capture light that wouldn't otherwise reach the panels. This combination can boost efficiency, particularly for bifacial panels, by channeling more reflected and direct light to the panels and potentially mitigating losses from non-ideal angles
How it works
Parabolic Concentrator: A Compound Parabolic Concentrator (CPC) uses a reflector with a specific parabolic shape to concentrate sunlight onto a target, like a solar panel, from a wide range of angles.
Vertical Bifacial Panels: Vertical panels have the advantage of generating energy from both their front and back sides (bifacial). They also have a more even energy production curve throughout the day, peaking in the morning and evening instead of just at noon.
Synergy: Placing a CPC around the panels can increase the amount of light the panels receive. The reflector captures sunlight that might have otherwise missed the panels and directs it to them. A secondary reflector can be used to further increase the amount of light captured.
Increased Efficiency: By concentrating more light onto the panels, this configuration can significantly increase the panel's energy output, potentially much more than a simple reflector.
Benefits
Higher Energy Yield: The concentrated and reflected light increases the total energy captured by the panels.
Improved Energy Profile: Vertical panels with east-west orientation produce a more consistent power output throughout the day, which can be beneficial for matching demand curves.
Reduced Cooling: Vertical panels stay cooler than traditional panels because they are shaded at noon, which improves their efficiency.
Space Efficiency: This system is more efficient at using land area, which is a benefit in areas where space is limited.
Considerations and limitations
Complexity: The design and construction of a CPC system can be more complex and expensive than standard panel installations.
Precise Aiming: Unlike a simple reflector, a CPC is designed to work over a range of angles, but it still requires some aiming to be effective.
Maintenance: Mirrors need to be kept clean to maintain their reflectivity, which adds to the maintenance workload.
Heat Generation: Concentrating sunlight can also increase the panel's temperature, which reduces its efficiency.

Terraforming is the theoretical process of transforming a planet or moon to make it habitable for humans and other Earth-like life. The concept involves altering an alien world's atmosphere, temperature, and surface conditions to resemble Earth's environment, such as adding oxygen to the air, creating liquid water on the surface, and establishing a stable climate.

Mars is the most commonly discussed candidate for terraforming, with proposals ranging from releasing greenhouse gases to warm the planet, to introducing microorganisms that could gradually produce oxygen over thousands of years.

Until recently, the idea of terraforming Mars has belonged to science fiction, a grand vision of transforming the cold, barren red planet into a world teeming with life. The idea has captured imaginations for generations, but serious scientists have largely dismissed it as impossible.

In a new paper posted to the arXiv preprint server, a team of researchers led by Dr. Erika DeBenedictis from Pioneer Labs argues it's time to take terraforming seriously as a research program, not because we should start tomorrow, but because recent breakthroughs in several fields have shifted the concept from impossible to merely very difficult.

Dr. DeBenedictis, the CEO of Pioneer Labs, authored a workshop summary that was prepared for the 2025 Green Mars Workshop, makes the case plainly and simply. Thirty years ago, terraforming Mars wasn't just hard, it was impossible. But new technologies, from SpaceX's Starship potentially slashing launch costs by a factor of a thousand, to advances in synthetic biology and climate modeling, have fundamentally changed the equation. The question is no longer whether terraforming is physically possible, but whether we should even pursue it and how we might approach such an incredible undertaking.

The workshop summary presents an intriguing narrative, beginning with possible planetary endpoints and tracing back to the steps required to reach them. The vision unfolds in phases. First comes warming, raising Mars's average temperature by tens of degrees within a few decades using engineered aerosols or greenhouse gases. Recent research suggests Mars harbors enough water ice to then form an ocean covering nearly 4 million square kilometers at depths of 300 meters. A temperature increase of around 30°C could begin melting these frozen reserves, creating conditions where liquid water could exist on the surface.

The second phase involves establishing microbial life. Here's where synthetic biology becomes crucial. Researchers propose engineering extremophiles, microbes that thrive in harsh conditions, combining traits like temperature tolerance, radiation resistance, and indifference to atmospheric pressure. These hardy organisms could potentially cover Mars with algae-like growth within decades, beginning the slow process of atmospheric transformation through photosynthesis.

The final phase stretches across centuries or even millennia, building an oxygen-rich atmosphere thick enough to support complex life. The team suggests starting within enormous domed habitats, 100 meters tall, where photosynthesis or water electrolysis could generate breathable air. Beyond these structures, spreading plant life would gradually contribute oxygen to the broader atmosphere, though this natural process alone would take a thousand years. Eventually though, human explorers could leave the protective domes and live on the planet's surface.

The research also highlights critical unknowns that must be addressed. What lies beneath the extensive ice sheets on Mars? How would dust storms behave in a warmer, wetter atmosphere? Are materials needed for large-scale water electrolysis, are they abundant enough on Mars, or would they require expensive importation from Earth?

Beyond the technical challenges lie the ethical questions. If we decide to terraform Mars, we will change it in ways that may not be reversible. Mars has its own planetary history, and terraforming would effectively end our opportunity to study that pristine record. If indigenous Martian life exists, even in microbial form, our interventions could destroy it.

The researchers argue that studying terraforming has immediate practical benefits for Earth. Technologies developed for Mars habitation, from desiccation-resistant crops to sustainable closed-loop systems, could directly benefit our home planet. Developing green technologies for space might offer a pathway to maturing them for terrestrial use.

I have to confess, as a not-so-closeted space enthusiast, there's something compelling about approaching planetary engineering not as immediate action but as rigorous research. The workshop summary doesn't advocate launching terraforming missions tomorrow. Instead, it calls for careful laboratory studies, detailed climate modeling, and perhaps small-scale experiments on future Mars missions to test localized warming strategies.

But, and it's a big but, before we consider transforming an entire world, we must thoroughly understand what we're working with and what we might be risking. The conversation has shifted from "could we?" to "should we, and if so, how?" and that represents genuine, considered progress.

AI Overview
NASA has funded the development of a concept for a "standing torso suit quadricycle for the moon" through a project called Chariot. Developed by a team at the Johnson Space Center, the Chariot is a multipurpose, modular lunar vehicle designed for astronauts to drive in a standing position, which gives it a "chariot-like" appearance.
Key features of the Chariot concept
Standing operation: The vehicle is specifically designed for astronauts to operate while standing, which allows them to explore more comfortably in their bulky spacesuits.
Modular design: The base mobility unit (chassis, wheels, batteries, and electronics) can be reconfigured with different attachments. These configurations allow it to serve multiple functions, such as transporting cargo, moving lunar soil (regolith), or carrying crew.
Hybrid operation: The Chariot is capable of multiple modes of control:
Onboard manual control: Direct operation by an astronaut on the vehicle.
Teleoperation: Remote control with small time delays from a lander or lunar habitation module.
Supervised autonomous control: Controlled from Earth with longer time delays.
Enhanced mobility: The standing position is intended to improve mobility for astronauts who are otherwise limited by the bulkiness of their spacesuits.
Broader lunar rover context
The standing torso suit quadricycle, or Chariot, is part of a larger effort to expand lunar mobility capabilities for the Artemis missions and beyond.
Replacing the original LRV: Like the Apollo-era Lunar Roving Vehicle (LRV), the Chariot is an unpressurized rover that will greatly expand astronauts' range and increase scientific productivity on the moon.
Supporting future exploration: In addition to crewed transportation, the Chariot is being developed to support cargo transport and other scientific objectives, including exploration of the lunar South Pole.
Complementing other vehicle designs: Other companies, such as Intuitive Machines and Lockheed Martin, are also developing unpressurized lunar terrain vehicles (LTVs). NASA has awarded contracts for the development and testing of several LTV concepts, ensuring a robust set of options for future lunar mission

For Space re Post #2216...

https://newmars.com/forums/viewtopic.ph … 28#p234828

What was your source for the post?  That was NOT a quote form GW Johnson.  The header above the post implies it was.

(th)

Yes, the Centaur upper stage has been human-rated for specific missions, notably as part of NASA’s Commercial Crew Program with the Atlas V rocket.

The Centaur upper stage, developed by United Launch Alliance (ULA), has a long history of use in launching satellites and interplanetary probes. For human spaceflight, however, it required significant modifications and rigorous certification to meet NASA’s safety standards.

?? Human-Rating the Centaur for Crew Missions
NASA’s Commercial Crew Program required launch vehicles to be human-rated to safely carry astronauts to the International Space Station (ISS).

ULA adapted the Atlas V rocket with the Centaur upper stage to support Boeing’s CST-100 Starliner capsule. This configuration underwent extensive review and testing to meet NASA’s NASA-STD-8719.26 human-rating standards.

Key upgrades included:

Redundant systems for propulsion and avionics.

Enhanced structural integrity to withstand crewed launch dynamics.

Safety protocols for abort scenarios and crew protection.

? Shuttle-Centaur Legacy and Safety Concerns
In the 1980s, NASA explored using a Shuttle-Centaur configuration to launch heavy payloads like the Galileo and Ulysses probes. This version of Centaur was designed to be carried inside the Space Shuttle and deployed in orbit.

However, after the Challenger disaster in 1986, concerns about the risks of carrying cryogenic fuel inside the Shuttle led to the cancellation of Shuttle-Centaur missions. This highlighted the challenges of human-rating high-energy upper stages.

?️ What Human-Rating Really Means
Human-rating involves more than just reliability—it includes designing for crew survivability, fault tolerance, and mission assurance.

The Centaur’s adaptation for crewed missions reflects a broader shift in spaceflight toward reusable, modular, and safety-focused systems.

If you're curious about how Centaur compares to other human-rated upper stages or want to explore its role in future missions, I’d be happy to dive deeper.

AI Overview
Space tugs can use a variety of fuels, including liquid hydrogen and liquid oxygen for high-efficiency chemical engines, non-toxic "green" propellants like nitrous oxide for smaller thrusters, and propellants for electric propulsion like xenon or argon. Nuclear thermal propulsion uses a liquid propellant, most often hydrogen, heated by a nuclear reactor to generate thrust, and some high-efficiency systems use propellants like hydrogen and oxygen for power generation.
Chemical propulsion

Liquid hydrogen/liquid oxygen:
A very efficient option for high-thrust chemical rockets, though liquid hydrogen is difficult to store long-term due to "boil-off".

RP-1 (kerosene), hydrazine, or nitrogen tetroxide (NTO):
These are less efficient than liquid hydrogen/oxygen but are "earth-storable" and don't suffer from the same long-term boil-off issues.

Green propellants:
Non-toxic alternatives to hydrazine are being developed, such as nitrous oxide-based fuels, which are used in smaller thrusters on some space tugs.

Electric and nuclear propulsion Nuclear thermal propulsion (NTP):
This concept uses a nuclear reactor to heat a liquid propellant (like hydrogen) to a very high temperature and expel it through a nozzle at high velocity, providing high thrust and efficiency.

Electric propulsion:
These thrusters are highly fuel-efficient but produce very low thrust, making them suitable for long, slow maneuvers rather than rapid changes in velocity. Examples of propellants include xenon, argon, or even bismuth.

Fuel cells:
Hydrogen and oxygen can be used in fuel cells to generate electricity for other onboard systems, which can then be used by electric propulsion or other equipment

Only a few small demonstration projects off the West Coast have harnessed the power of waves and tides. Costs are high and hurdles are challenging.